JP3043457B2 - Monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring apparatus for monitoring the presence or absence of a moving object such as a human from an image captured by an ITV camera or the like.

[0002]

2. Description of the Related Art Conventionally, as a monitoring apparatus of this type, a monitoring area is set on an image obtained by photographing a whole monitoring area by a television camera, and a luminance change of each pixel at a certain time interval in the monitoring area. Is known to detect the presence of a moving object and output an alarm such as “the presence of an intruder”. In the monitoring device, since only the luminance change of each pixel is used as a criterion, for example, intrusion into the monitoring area such as flying fallen leaves or paper debris, snowfall, even when the TV camera shakes or the like causes a luminance change, There has been a problem that these are erroneously detected as moving objects to be monitored by humans or the like.

In view of this point, the present applicant has filed a Japanese Patent Application No. Hei.
No. 2475 has previously proposed a monitoring device that obtains a block based on the number of pixels having a predetermined change in luminance and detects the presence of a moving object in consideration of the number of blocks. According to this monitoring device, it is possible to prevent the erroneous detection described above and detect only a moving object having a predetermined size as a monitoring target.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application No. Hei.
Also in the monitoring device according to No. 302475, measures against steady disturbance such as electric noise included in a video signal generated on the entire screen and determination of the size of a moving object are not sufficient, and higher accuracy is obtained. There has been a demand for the realization of a monitoring device capable of monitoring the traffic. The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to completely remove noise included in a captured image, accurately determine the size of a moving object, and determine its existence. It is an object of the present invention to provide a monitoring device capable of reliably detecting and displaying.

[0005]

In order to achieve the above object, the present invention focuses on each pixel determined to constitute a moving object based on a temporal change in luminance value, and a fixed number of pixels around the pixel of interest. All of the target pixels where the above pixels exist
And reduction conversion means for extracting a detection pixel, all the detection pixels overall size output from the reduction conversion unit,
It is determined that the threshold value is equal to or greater than the threshold value corresponding to the size of a moving object as a monitoring target such as a human, and that the detection pixel exists in a monitoring area set on an image captured by a television camera. Determining means for detecting the presence of a moving object to be monitored.

[0006]

According to the present invention, in the monitoring area,
The presence of a moving object is detected from the temporal change of the luminance value of each pixel. Then, for each pixel determined to constitute the moving object, the reduction conversion unit extracts, for example, a pixel having at least two pixels above, below, left, and right as a detection pixel, thereby reducing noise due to steady disturbance or the like. Is removed. For the binarized image signal from which the noise has been removed in this way, the judging means comprising a comparator determines, based on the number of detected pixels, that the size of the moving object is greater than or equal to a predetermined threshold value and that the moving object is within the monitoring area. And the presence of a moving object to be monitored is detected. With this detection signal, an alarm such as “there is an intruder” is issued,
An image showing a moving object is displayed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of this embodiment. As shown in FIG. 1, the monitoring device includes a television camera unit 1, a setting unit 2, a control unit 3, and an alarm unit 4. First, the television camera unit 1 includes a television camera 11 such as an ITV camera for imaging a predetermined monitoring area,
A first-stage amplifier 12 for amplifying the video signal a output from the television camera 11, an addition amplifier 13 to which a video signal b as an output thereof and a logical product video signal u output from a logical product means 38 described later are inputted; A display device 14 such as a monitor television for displaying an image based on an image signal c as an output thereof, and a buffer amplifier 1 to which the video signal b is input
5 is provided.

Next, the setting section 2 includes an area setting section 21 such as a light pen for setting a predetermined monitoring area in the image of the monitoring area displayed on the display device 14, and an output from the area setting section 21. Area memory 22 for outputting an address of a pixel contained therein based on coordinate data m
And a parameter input unit 23 such as a keyboard for inputting a parameter n for setting threshold values q and r described later.
And a luminance change amount threshold value q corresponding to the parameter n
And a threshold memory 24 for outputting a magnitude threshold r. The area setting unit 21 may be a cursor input unit using a mouse or a keyboard.

The control section 3 includes a timing control circuit 31 for generating timing signals e and h based on a synchronization signal separated from the video signal d from the buffer amplifier 15;
An A / D conversion circuit 32 that converts an analog video signal d into a digital value as a luminance value of each pixel using the timing signal e as a sampling clock, and a video memory that stores the luminance value f from the A / D conversion circuit 32 33, and the previous luminance values g, A output from the video memory 33.
Based on the current brightness value f output from the / D conversion circuit 32 and the brightness change threshold value q from the threshold memory 24, whether or not the brightness change amount of each pixel is equal to or greater than the threshold value q A binarized memory 35 for storing binarized data i output from the comparator 34 for a pixel whose luminance change amount is equal to or greater than the threshold value q,
The binarized image signal j output from the binarized memory 35
, A reduction conversion circuit 36 for performing a reduction conversion process to be described later to remove noise, a binary image signal k output from the reduction conversion circuit 36, a magnitude threshold r from the threshold memory 24, and an area. A comparator 37 that determines whether or not the moving object is a monitoring target based on the address signal p from the memory 22, and a logical product of the detection signal s from the comparator 37 and the binary image signal k from the reduction conversion circuit 36 And logical product means 38.

Further, the alarm section 4 comprises an alarm indicator 41 which receives a detection signal s from the comparator 37 and operates an alarm lamp and an alarm buzzer.

Next, the operation of the entire embodiment will be described.
First, the video signal b from the television camera 11 via the first-stage amplifier 12 is sent to the addition amplifier 13, while being sent to the A / D conversion circuit 32 and the timing control circuit 31 via the buffer amplifier 15. The A / D conversion circuit 32 obtains a luminance value f for each pixel according to the timing signal e, stores the luminance value f at a predetermined address of the video memory 33, and sends the luminance value f to the comparator. In the comparator 34, the current luminance value f
And the previous luminance value g read from the video memory 33
Is calculated. Here, the time interval between the current and previous brightness values is set by the timing signal e. The comparator 34 compares the amount of change in the luminance values f and g with the threshold value q of the luminance change amount. "1" is output as the binary data i. The binarized data i is stored at a predetermined address of the binarized memory 35. Note that the comparator 34 may detect the change rates of the current and previous brightness values f and g and compare the detected change rates with the brightness change rate threshold value.

The reduction conversion circuit 36 is provided with the binarized memory 3
A reduction conversion process is performed based on the binarized image signals j for a plurality of pixels output from the pixel 5 to remove electrical noise contained in the entire image or noise caused by a luminance change due to snowfall or the like. Hereinafter, this reduction conversion processing will be described with reference to FIG.
This will be described with reference to FIG. That is, in the reduction conversion circuit 36, based on the binarized image signal j, the pixel 5 adjacent to the pixel 5 shown in FIG.
The binary data of a, 5b, 5c, 5d is "1" or "0"
When the number of pixels that are “1” is two or more (three or more including self), the binarized data of the pixel of interest 5 is set to “1” again. It is extracted as a detection pixel.

For example, if the binarized image signal j is as shown in the upper part of FIG. 3, even if the binarized data is temporarily "1" due to electrical noise or the like included in the video signal,
Pixels that do not have a fixed size and are scattered in the image are removed by replacing the binary data with “0” as a result of the reduction conversion process. A binary image signal consisting of only the image data is newly generated. In other words, the reduction conversion circuit 36 removes the scattered noise in this manner, thereby extracting only pixels recognized as constituting a moving object to be monitored, such as a human. In addition, according to the distance between the television camera 11 and the imaging target or the like, eight pixels around the pixel of interest are searched to determine whether the binary data is “1” or “0”. In this case, the pixel of interest may be extracted as a detection pixel.

The binarized image signal k from which noise has been removed by the reduction conversion circuit 36 is stored in the threshold value memory 2
4 together with the magnitude threshold value r from 4 and the address signal p from the area memory 22.
The comparator 37 outputs “1” of the binary image signal k.
From the total number of pixels (detection pixels), it is determined whether or not the total size is equal to or greater than a threshold value r. It is determined that it corresponds to the moving object to be monitored. Then, it is also determined whether or not the moving object is within the monitoring area defined by the address signal p. If the judgment is affirmative, the moving object detection signal s is output. here,
In the present embodiment, after removing noise by reduction conversion, 2
Since the binarized image signal k is compared with the size threshold value r, noise does not adversely affect the determination of the size of the moving object, and highly accurate determination can be performed. The alarm annunciator 41 notifies the presence of a moving object such as an intruder in the monitoring area by the detection signal s.

On the other hand, the detection signal s is sent to the AND means 38 together with the binarized image signal k from the reduction conversion circuit 36. The AND means 38 allows the binary image signal k to pass only when the detection signal s is output, and outputs the AND video signal u
Is output to the addition amplifier 13. The addition amplifier 13 adds and amplifies the video signal b from the first-stage amplifier 12 and the logical product video signal u, generates an image signal c in which a moving object is superimposed in the monitoring area, and displays the image on the display device 14. Let it. Here, the image indicating the moving object may be, for example, a black-and-white inverted image. Further, not only the outer shape of the moving object itself is displayed, but also the presence of the moving object may be displayed in some form, for example, by displaying a position where the moving object has entered by a special symbol.

FIGS. 4 to 6 show changes in an image in the process of this embodiment. First, it is assumed that an image corresponding to the monitoring area by the television camera 11 is as shown in FIG. 4, and that the monitoring area E is set by the area setting unit 21. When the object M moves from the solid line to the direction indicated by the broken line in the area E, the comparator 34 detects the moving object M, and the binary memory 3
The image corresponding to the binary image signal j of No. 5 is as shown in FIG. At this time, if the background is stable, only the moving object M is detected. However, due to disturbance such as electric noise included in the video signal, many spots are scattered in the actual image as illustrated. By performing the above-described reduction conversion processing on the binarized image signal j, the spots are removed, and an image as shown in FIG. 6 in which only the moving object M is finally extracted can be obtained. Count the detected pixels for this image,
When the size is equal to or larger than the threshold value r, an image of the moving object M is displayed, and an alarm is issued at the same time.

[0017]

As described above, according to the present invention, even when noises are included in a video signal due to disturbance that occurs steadily, these noises can be removed by the reduction conversion means. It is possible to detect only a moving object to be monitored with high accuracy by removing a change in luminance of a pixel due to noise, snowfall, shaking of a television camera, or the like. Further, since the noise component is not displayed on the screen, a display screen that is easy to see can be realized.

Furthermore, since the entirety of the detected pixels after noise removal is compared with the size threshold value, there is no inconvenience that the size is erroneously recognized due to the presence of noise, and the size of the moving object can be more accurately determined. Can be determined.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of pixels in a binary image signal.

FIG. 3 is an explanatory diagram of a reduction conversion process.

FIG. 4 is a diagram illustrating an image captured by a television camera.

FIG. 5 is a diagram showing an image of the image of FIG. 4 before reduction conversion.

FIG. 6 is a diagram showing an image after reduction conversion of the image of FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 TV camera unit 2 Setting unit 3 Control unit 4 Alarm unit 5, 5a, 5b, 5c, 5d Pixel 11 TV camera 12 First stage amplifier 13 Addition amplifier 14 Display device 15 Buffer amplifier 21 Area setting unit 22 Area memory 23 Parameter input unit 24 Threshold memory 31 Timing control circuit 32 A / D conversion circuit 33 Video memory 34, 37 Comparator 35 Binarization memory 36 Reduction conversion circuit 38 Logical product means 41 Alarm alarm E Monitoring area M Moving object

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G08B 21/00 G08B 13/196 H04Q 9/00 311 H04N 7/18

Claims (1)

(57) [Claims] A monitoring device that detects the presence of a moving object from a temporal change in the luminance value of a pixel constituting an image captured by a television camera, issues an alarm, and displays the presence of the moving object . Focusing on each pixel determined to constitute the moving object by a temporal change, reducing conversion means for extracting all the pixels of interest such that a certain number of pixels or more exist around the pixel of interest as detection pixels, The entire size of all the detection pixels extracted by the reduction conversion means is equal to or larger than a threshold value corresponding to the size of the moving object to be monitored, and the detection pixels are set on the captured image. And a determination means for determining the presence of the moving object to be monitored by determining that the moving object is present in the monitoring area.